As predicted, Wednesday's tenth I/O conference saw the launch of the Google Assistant voice recognition tool to the iPhone.

The app will be restricted to just the United States at launch, with voice-based queries processed in a similar way to the existing Google search app. Due to Apple's control over the iOS architecture, users will not be able to replace Siri with Google Assistant, and will need to enter the app in order to perform verbal requests.

Other enhancements to the package coming soon include the new Google Lens image processing algorithm, with text interpretation related to location, an "always on" approach, all demonstrated at the 2017 I/O Keynote. The company is adding 10 languages before the end of the year, beyond just English.

Google Assistant is considered to be more advanced than the existing Google Voice Search tool, due to being able to interpret context within a conversational-style query, such as follow-up questions. For example, asking "How old is he" after the query "Who is the President of the United States" would provide the President's age in Google Assistant, whereas competitors typically treat each individual statement as a separate query.

Google initially launched Google Assistant, its next-generation artificial intelligence tool, as part of the Allo messaging app released last year. The "preview edition" of Assistant allowed users to interact with the messaging bot, providing responses to queries within the Allo app as part of a conversational thread.

Google product management director Gummi Hafsteinsson hinted at the possibility of Google Assistant appearing on iOS in March at Mobile World Congress. While not having "anything to announce" at the time, Hafsteinsson suggested "I think the general philosophy is that we would like to have the Assistant available to as many people as possible."

Apple has not stood still with Siri, Google Assistant's main competition, with a string of machine learning and language processing acquisitions suggesting there could be a major upgrade to Siri coming as part of the next major iOS update. Last year, Apple opened up the digital assistant to third-party developers with the release of an SDK, enabling apps to perform actions based on Siri queries, such as payments and sending messages.

Update: The Google Assistant app is now available for download. The app takes 256MB of storage space, and runs on any device capable of running iOS 9.1 or greater.